1. Field of the Invention
The present invention is directed to strength loss resistant methods for treating cotton toweling and related fabrics with cellulase so as to impart permanent softening to these fabrics. In particular, the methods of the present invention involve the application of a specified amount of cellulase onto the surface fibers of cotton toweling and related fabrics so as to result in permanent softening of such fabrics. On the other hand, since a specified amount of cellulase is applied only onto the surface fibers of such fabrics, the base fibers (i.e., the interior fibers) of the fabric are not exposed to significant quantities of cellulase. In turn, the interior fibers are not significantly degraded by cellulase and accordingly, strength loss in the treated fabric is reduced as compared to the strength loss arising from treating all of the fibers of the fabric with cellulase.
The methods of the present invention are particularly suitable for use in both a continuous and batch process for treating cotton toweling and related fabrics with cellulase.
2. State of the Art
The use of cellulase to impart permanent softening properties to cotton toweling and related materials is well known in the art. For example, cotton toweling can be treated in a batch or continuous process whereby the treated fabric is washed (immersed) in a cellulase solution at specified conditions. Under such conditions, both the interior and the surface cotton fibers of the fabric are exposed to the cellulase solution. After treatment, the fabric is generally rinsed and dried. Under these conditions, such treatment with cellulase results in permanent softening for the fabric.
However, there is a problem with the treatment of cotton toweling and related fabrics in the manner of the prior art. Specifically, when treated in heretofore known methods for imparting permanent softening, such fabrics experience undesirable weight loss, reduced tensile strength and reduced absorbency. These detrimental attributes can be so severe as to render the treated fabric a poorer quality product as compared to the fabric prior to treatment.
In view of the above, methods for treating cotton toweling and related fabrics which impart permanent softening properties to such fabrics but which also result in reductions in the undesirable properties imparted by prior art processes would be particularly advantageous.